Sulphurized cinchona bark alkaloid



Patented May 16, 1933 UNITED STATES PATENT OFFICE i i GEORGE LUTZ, OF ROCKY RIVER, OHIO, ASSIGNOR TO THE GRASSELLI CHEMICAL COMPANY, OF CLEVELAND, OHIO, A CORPORATION'OF DELAWARE SULPHURIZED CINCHONA BARK ALKALO'ID NoDrawing. Original application filed December 16, 1931, Serial No. 581,518. Divided and-this application filed April 23,

This invention relates to processes of cleaning and pickling metal articles by the action of acids thereon, and is particularly directed tothe use in cleaning and pickling baths of certain organic substances which I have found to have the property of inhibiting the action of acids upon the metal;

itself, without in any substantial manner hindering its action on the oxide, rust and scale or' other undesirable incrustations which such operations are intended to remove from the metal.

I have found that sulphur or substances which release sulphur on heating in contact with nitrogenous organicsubstances will react with' cinchona bark alkaloids to form new substances which, in the absenceof a more thorough understanding .ofthe chemical reactions involved, I shall designate as sulphurized cinchona bark alkaloids. Typical representatives of the cinchona bark alkaloids which react with sulphurare quinine, quinidine, cinchonine and particularly quinoidine, the by-product of the extraction" of the medicinal alkaloids from the cinchona bark.

I further found that these novel, sulphurized alkaloids act as inhibitors in cleaning operations involving the action of nonoxidizing acids uponzmetalarticles.

My invention comprises these novel sulphurized cinchona bark alkaloids and their application to the control of the action of acids upon metals. v

My novel sulphurized compounds are prepared by heating the alkaloids with elemental sulphur, sulphur chloride or other substances which release sulphur on heating,

either direct or in the presence of a' catalyst,

40 such as aluminum chloride. V

A preferred process for preparing sulphurized quinoidine or sulphurized oinchona bark alkaloids is as follows:

The quinoidine or cinchona bark alkaloid is first melted; in anysuitable receptacle 1932. Seria1No. 607,226. I

until fluid. A definite amount of powdered su l hur is then stirred into the molten mass wlt continued heating until a sudden rise 1n temperature is noted, at which pointthe heating is discontinued. The sudden rise in temperature is accompanied by vigorous reaction with copious evolution of H S and the mass is stirred constantly to prevent excess foaming. Thesudden rise intema peraturebrings the temperature up to 1359 y G.140 0., and the mass iskept at this temperature for at least 15 minutes before cooling. 7

The amount of sulphur used in preparing these. sulphurized compounds; may vary 01 from 5 to 20% by weight, although in my preferred process I use ,about 15% b weight, 7

wThese'sulphurized compounds may also be prepared by heating quinoidine orthej ization. processes are substantially the same.-

in properties. They vary in the amount of sulphur combined according to the amount of sulphur or-sulphurization reagent used, and are probably mixtures of various sulv phurized products and from 5 to 15% S.

They are yellowish to reddish-brown, brittle masses which are easily ground to powder. I o j They have no definitely known chemical composition, though from analogy with the sulphurization .of aromatic amines, it, can be assumed that the sulphur enters by replacement of hydrogen into the nuclei of the alkaloids. 3 j

These sulphurized alkaloids have no defi nite melting (point, theymelt' between about.

7 that. is to say, higher than the raw materials.

,They are insoluble .in

contain anywhere 5 aqueous caustic a1, 2'

Inhibitor. *I have found" that my novel sulphurized cinchona bark alkaloids pre sent .certain advantages over the original alkaloids"in' metal cleaning operations in in the cleaning acid solution and have a higher pickling efliciency.

Pickling fandmetal cleaning operations x involve commonly the use .of, dilute, nonoxidizing acids, such as sulphuric, hydrochloric, acetic, formic, aqueoussolutions' of acid sulphates, etc., and such baths are used for numerous purposes, of which pickling in steel mills is the most typical representative'. The composition, concentration, temperature and other factors vary with dif-* ferent baths, but the underlying; principle comprises in all cases the removal of unclesirableincrustations by the action of the acid. The bare metal so obtained is then in the absence of an inhibitor unavoidably subjected to attack by the acid with unnecessary loss of metal, weakening of the article and unnecessary consumption, of acid.

My novel inhibitors, comprising sulphurized quinoidine and othersulphurized cinchona bark alkaloids are eflicient inhibitors with the various commonly used pickling and cleaningjacids; The application of my "invention to acid pickling and acid metal cleaning operations does not involve any change in the baths and operation-thereof, except for the addition'of a small amount of theseinhibitors. Less than' of 1% of sulphurizedquinoidine added to an acid pickling or cleaning bath will, to a large extent, if not entirely, prevent the attack: of the base metal "under the conditions where 'all'undesirable incrustations are removed. In some instances amounts of 1% or less, are efiicient and suflicient for all Purposes. In pickling operations the concentration of acid in the picklingbath varies from 5 "to 10%, and the temperature from 140 to 190 F. Laboratory tests by the so-called loss in weight method which consists of a.

beaker-scale pickling operation using a 6% 'ing the loss in weight of the steelafter oneh'alf-ihour, and after tWo'one-hou'r periods of immersion after the firsthalf hour im- Inersion in the-bath, showedmy novel inhibitors to have the following-inhibiting eflicienc'ies when the s'ulphuri'zedproducts are that the new derivatives are easier soluble V sulphuric acid pickling bath, at 180 F., notcompounded at the rate of 10% with 90% inert ingredients Concentration of compounded inhibitor .05 percent .1 percent Period of pickling 1 2 3 1 2 3 Timeofpickling (minutes) 30 60 30 60 60 Scale included Yes No No Yes No No Active ingredient com- I position Reacted with Qulnoidine,

I sulphur, perm i l 85 1 5 72.5 752.4 82.6 76.2 97.7 97.5 20 64.9 90.4 80.2 77.4 98.0 98.0 15% sulphur chloride 77.6 88.9 77.3 79.1 97.7 973 100 None 82.9 34.6 88.9 44.6

Cinchcnine Reacteii with kaloid, sulphur, perpercent cent 10 81.7 78.2 63.5 81.6 97.04,.9a1 None 40.6 61.9 42.9

first period includes the'loss in weight due to adhering scale and .other incrustations which Varies on the d'fi'erent specimens oi steel. In the second and third periods the loss is due to loss of bare metal only. i f

Four inhibited acids,weref prepared b dissolving sulfurized quinoidine in cold 18 B. commercial muriatic acid at the rate of 10o Portions of these acids were then-diluted to 15% acidity as I IGl and the inhibiting on 26 gauge black 1%, .5%, .1% and 02%.

efficiency was determined sheet steel at 80-90 F.. I

The first period of pickling consisted of efficiency.

' Results obtained [Inhibiting efficiency of '18 B. Commercial inuriatle acid containing 1%, 5%, 1% and .02%.su1phnrized qumoldine diluted to 15% 'acidity at 80- 90 F. .'on

"Similar efficiency figures were iobtaiiied with quinine and qu'inidine sul' hurized with 5, 10, 15 or 20% sulphur 'wit outor'with.

for instance 2% aluminum chloride?" In the above table the efliciency for the;;

p 5 hours during which the scalewas-removed and the second period of pickling; consisted; ofilfi hours after the first 5 hours. The loss in weight, of the steelwas noted for each period and calculatedgto per cent inhibiting This is a division of my application Ser. No. 581,518, filed December 16, 1931.

I claim: 1. An organic compound containing nitrogen and sulphur, a yellowish to reddish brown, resinous substance having no sharp melting point, which is insoluble in aqueous caustic alkali but soluble at least to a large extent in dilute mineral acid and has the property of inhibiting the action of acids upon metals, said compound being sulphurized quinoidine.

2. An organic compound containing nitrogen and from about 5 to sulphur, a 1 reddish brown, resinous substance melting above about 135 0., which is insoluble in aqueous caustic alkali, soluble in chlor0-' form and nearly entirel soluble in'dilute mineral acid, and has tlze property of inhibiting the action of acids upon metals, said compound being sulphurized quinoidine obtained by heating quinoidine for 15 to 20 minutes at about 135 to 140 C. with from about 5 to 20% of its weight of sulphur. In testimony whereof, I afiix my signa-- ture.

GEORGE LUTZ. 

